Margie Carsen is the mother of Flynn Carsen. She is a proud and frequently protective parent, who worries that her bookish son will never look up long enough to 'find a nice girl' and so works to at least occasionally throw them in his path. She was Jerry's one true love, although he was too slow getting to the point and Flynn's dad swooped in.
Although she does not appear in "The Librarian: The Curse of the Judas Chalice", presumably some time between that and "And the Crown of King Arthur" (and closer to the former) Margie passed away, since Flynn tells Eve during their first conversation in the Annex that Judson was there for him when his mother died, and that Judson himself has been deceased for five years.